1. Field of the Invention
The present invention generally relates to apparatus for planting a shaft in a base, for supporting the shaft in a generally vertical orientation, and particularly to apparatus for driving a shaft into a granular base. The vertically oriented shaft may be used to support an umbrella or other structure.
2. Description of the Prior Art
A vertical support member planted in a base is a common element of many static structures. A vertical support member may be planted in a soil base by digging a hole, setting the support member, and filling the hole. A vertical support member may also be driven into the soil base by positioning the support member at a desired location and repeatedly hammering the support member, to advance the support member into the soil. When hammering a support member, it is common practice to place a drive cap on the upper end of the support member to avoid deforming the support member during hammering, so that the shape of the support member will be preserved to facilitate the attachment of other structural elements.
When individuals visit a beach, for recreation, temporary static structures, such as umbrellas, sports equipment, and flagpoles are often erected. These structures are typically supported by a shaft planted in the granular base of beach sand. The granular nature of the sand makes planting of a shaft relatively easy and several methods may be used. A hole may be hand dug, the shaft may be placed in the hole and the hole may be refilled. Mounting sleeves are available with a spiral shaped rod projecting from a lower end. The sleeve may be turned, in the manner of a corkscrew, to advance the sleeve into the base. The upper portion of the sleeve is provided with an opening for receiving the center pole of an umbrella or other article. Finally, articles, which may be disassembled to separate a lower portion of the shaft from the article, may be planted by hammering the lower portion of the shaft into the base and subsequently reassembling the article to support the umbrella or other article overhead.
The various methods of planting a shaft in a granular base have certain drawbacks. The process of hand digging a hole can be somewhat tedious. Below the surface of the beach, the sand becomes moist and more compacted. Digging a hole of sufficient depth to support the article is difficult and inconvenient. The mounting sleeve, with the spiral rod, is relatively easy to plant but the device must be carried and stored. When individuals visit the beach, it is desirable to minimize the amount of items, which must be carried. The method of driving the shaft into the base requires a hammer and perhaps a drive cap to protect the top of the shaft, both which items must be carried.
There is a need for a simple and convenient apparatus for planting a shaft in a granular base.
There is a need for a driving apparatus that is integrated with the shaft to be driven into the granular base.
There is a need for a driving apparatus, which is detachable from the shaft to be driven.
There is a need for a driving apparatus, which facilitates removal of the shaft from a granular base.